Circuit controlling device



E. KNEASS 2 Sheets-Sheet 1 CIRCUIT CONTROLLING DEVICE Filed Jan. 18,1939 Ftc/TZ.

March 11, 1941.

I N VEN TOR.

v ATTORNEY.

March 11,, 1941'. E. KNEASS CIRCUIT CONTRQLLING DEVI CE 2 Sheets-Sheet 2Filed Jan. 18, 1939 mm QM INVENTOR.

My 62m A TTORNEY.

Patented Mar. 11, 1941 PATENT OFFICE 1 CIRCUIT CONTROILING DEVICEEdwards Kneals, Philadelphia, Pa., assignor to I-T-E Circuit BreakerCompany, Philadelphia, Pa., a corporation oi New Jersey ApplicationJanuary 18, 1939, Serial No. 251,487

'lClaims.

My invention relates to circuit-controlling devices, and particularly toswitches having an operating member for eifecting relative movement ofthe switch contacts into and out of circuitclosing position and foractuating mechanism which clamps the contacts to each other.

In accordance with my invention, the transition from relative movementof the contacts to actuation of theclamping mechanism is controlled bymeans which is continuously operatively related to the operating memberduring the transition; more particularly, the control means comprisescam structure which precludes actuation by the operating member of theclamping mechanism except when the contacts are in circuit-closingposition and which precludes relative movement of the contacts unlessthe clamping pressure has first been to suitable extent relieved; morespecifically, the cam structure imposes upon the operating membersuccessive components of motion insuring, in predetermined sequence,clamping or unclamping of the contacts and their relative movement intoor out of circuit-closing engagement.

My invention further resides in the features of construction,combination, and arrangement hereinafter described and claimed.

For an understanding of my invention, and for illustration of difierentmodifications thereof, reference is to be had to the accompanyingdrawings, in which:

Fig. 1 is a side elevational view of a switch with its contacts clampedin closed-circuit position;

Fig. 2 is a sectional view taken on line 2-2 of Fig. 1;

Fig. 3 is a top plan view, partly in section, taken on line 3-3 of Fig.1;

Fig, 4 is a front elevational view of Fig. 1, taken on line 4-4 of Fig.2, with parts omitted and with the contacts unclamped and in opencircuitposition;

Fig. 5 is a side elevational view of a modified form of switch with itscontacts clamped in closed-circuit position;

Fig. 6, partly in section, and with parts omitted, shows the switch ofFig. 5 with its contacts unclamped and in open-circuit position;

Fig. 7 is a front elevational view of a multipole switch, one switchpartly in section and with parts broken away.

Referring to Figs. 1-4, the movable contact structure of the switchcomprises the two movable blades I. I, pivctaliy mounted on oppositesides of the fixed contact or terminal 2 upon the pin or stud 3 whichextends through or projects from the terminal 2. The operating member orarm 4 for swinging movable contact structure I, I into and out ofengagement with fixed terminal 5 or contact 5 is mounted upon the pin 6which passes through the blades I, I. As more clearly appears in Figs.1-3, the pin 6 rotates with the arm 4 when the operating handle I of thearm is swung through an arc having the axis A of the 10 pivot pin 6 asits center. Rotation of the pivot pin with the operating arm may beinsured in any desired manner; in the arrangement particularly shown,the operating arm 4 has a noncircular hole which snugly receives acorrespond- I ingly shaped central portion 6A of the pivot pin. Theouter ends of the pivot. pin 6 threadably engage the clamping bars 8, 8which are preferably recessed at their lower ends to receive the ends ofthe pivot pin 3 for the movable contact blades 2 One end of pivot pin 6is provided with a righthand thread, and the other end of the pivot pinis provided with a left-hand thread; therefore upon rotation ofoperating arm 4 in one direction about axis A, the clamping plates 8 aremoved toward each other, and for reverse rotation of the pin, the plates8 are moved away from each other. This same result may be accomplishedby using a pivot pin threaded only at one end and with a head orshoulder at its other end which bears, either directly or through asuitable bearing, against the outside of the associated clamping plate.However, the illustrated construction is preferred.

The cam 9, which preferably extends from the lower terminal 2, isprovided with a continuous slot III for guiding a cam follower II,preferably a roller, pivotally supported by the pin I2 extending betweenthe side members 4a of the switch operating arm. 'I'hecurved sides ofthe upper section of slot I0, above cusp C, have axis A as their centerof curvature; consequently, when the contacts are clamped in theircircuitclosing position, Fig. 1, the operating handle I, which may bemanually operated, or connected to any suitablemotor device forautomatic operation, can be swung only in an are having the axis A asits center. When the movable contacts I, I are in the-closed-circuitposition shown in Fig. 1, they therefore cannot be movedfrom thatposition by the operating handle 1 until the roller II has passeddownwardly beyond the cusp C of slot I0. It is thus insured the pressurebetween the movable blades I, I and the fixed terminals 2, 5 must besuitably reduced before the movable contact structure I, i can berotated about its pivotal axis B.

For continued downward movement of the operating handle from theposition shown in Fig. 1 to the position shown in Fig. 4, the operatingarm 4, as above described, first rotates about its axis A until roller|l passes cusp C of the slot or groove l; thereafter, the operating arm4 and the movable contact structure rotate in a fixed angular relationwith respect to each other about the pivotal axis B of the movablecontact structure. For that range of its movement within the limits ofthe lower arcuate section of the groove l3. below cusp C, the operatingarm 4 cannot be rotated about its pivotal axis A to effect movement ofthe clamping members 3 either toward or away from each other, becausethe sides of this lower section of the cam groove I. have axis B astheir center of curvature.

It is thus insured the movable contact structure moves into and out ofengagement with the fixed terminal 3 while under the desired clampingpressure which cannot, accidentally or otherwise, be changed by impropermanipulation of the operating arm 4. The cam 3 which continuouslycontrols the position of the operating arm 4 throughout its movement ofthe contact structure and through the transition from such movement toactuation of the clamping bars 3 precludes actuation of the clampingmembers 3, 3 when the contacts are out of engagement with each other,and permits actuation of the clamping bars to increase or decrease thepressure only when the movable contact structure is in theclosed-circuit position of Figs. 1 and 2.

The switch operator to open or close the switch merely moves the handleI from one limiting position to the other without need for attention onhis part to rotate arm 4 about its axis A to proper extent before theblades I, l are moved toward or away from closed-circuit position; thecam 9 for continuous movement of arm 4 in either direction imposes uponthe movable contact structure and the clamping bars successivecomponents of movement of proper magnitude, and controls the transitionfrom or to contact actuation to or from actuation of the clamping bars.

In the particular construction shown in Figs. 1 to 4, the ends of thecam slot i0 define the limits of movement of the operating arm 4, andthe cusp C divides the slot into two distinct sections; the upperarcuate section defines the range of movement within which the operatingarm 4 can actuate only the clamping members 3 and the lower arcuatesection defines the range of movement within which the operating arm 4can only effect movement of the contacts I, I toward or away from thefixed terminal 3. Preferably the cusp C is quite sharp, clearly todefine the transition between contact clamping and contact movement; tothe same end, the width of the slot should closely correspond with thediameter of the roll The transition of control from actuation toclamping of the movable contact structure, imposed, respectively, by thecam surfaces Illa and lb, ispreferably, as shown, immediate, at theregion of cusp C; and, in any event, whether the transition period beshort or prolonged, the mechanical connection between the operatingmember 4 and the movable contact structure remains the same throughoutboth components of control and the intervening transition. Theforegolngis distinguished in practical aspects from the case where the operatingmember is latched to the movable contact structure during movementthereof to circuit-closing position, which requires tripping of thelatch before performance of the clamping operation; the position of theoperating member with respect to the movable contact structure at whichtripping of the latch occurs is indeterminate and variable as betweensuccessive operations of the switch, and so has the practical defect asbetween successive operations of the switch that both thecircuit-closing position of the movable contact and the concurrentclamping pressure vary. Besides, the position of the operating memberwith respect to the movable contact structure at which relatching occursin successive operations of the switch is variable and indeterminate,and so has the practical defect that as between successive separation ofthe contacts the contact pressures during separation may differ tosubstantial extent.

In the preferred construction herein shown, the relations between thedistance between the axes A, B and the lengths of the radii of curve.-ture of the arcuate cam surfaces Illa, lllb, are such the transitionfrom contact actuation to clamping, and vice versa, is immediate, andoccurs at a position of the operating arm which is definitely the samefor successive operations of the switch.

Referring to Figs. 5 and 6, the switch construction is, in general,similar to that shown in Figs. 1 to 4; the fixed contacts 22 and 23 aremounted on insulators I secured upon base 34; the movable contactstructure comprises a pair of blades 2|, 2| mounted upon a pivot 23extending from or projecting through the lower terminal or contact 22which, in this modification, is provided with integral extensions 22Afor connection to bus bars. Upper contact 23 has extensions 25A for busbar connections. The clam-ping bars 28, 23, for pressing the movablecontact blades 2|, 2| against the lower terminal 22 and the upperterminal 25, are threadably received by the opposite ends of the pivotPin 26 which is secured to an operating arm 24 connected by links 33which extend through the switch base 34 to lever 35 on shaft 40connected by arm 4| and link 38 to any suitable operating means; forexample, a manually actuatable handle, or to a solenoid or other motormechanism.

The cam 23 having the same purpose and function as the cam 3 of Figs. 1to 4 has one arcuate surface 23a corresponding with the upper section ofcam groove Ill, Figs. 1 to 4, and a second arcuate section 29bcorresponding with the lower section of cam groove I0, Figs. 1 to 4.When the contacts are in the closed-circuit position of Fig. 5, theoperating linkage, including links 33, 36, and arms 24, 35 and 4|, canbe actuated only to release or tighten the clamping bars 23; thisbecause arm 24 can then rotate only about axis A, the center ofcurvature of are 290; the engagement between cam follower 3| and the camsurface 29a prevents any motion of the contact blades 2| about theirpivotal axis B.

For continued upward movement of link 36 from the position shown in Fig.5, the arm 24 is first swung in counter-clockwise direction about itspivot A suitably to reduce the pressure exerted by the clamp bars 23upon the contacts 2|; as soon as the cam follower 3| passes the cusp Cof cam 29, further upward movement of link 36 eifects clockwise rotationof the movable contacts 2| about their pivotal axis B to open theswitch.

So long as the cam follower 3| is in engagement with the arcuate surface29b of cam 29, movement of the operating member 38 can effect onlymovement of the contacts 2| toward or away' from the fixed terminal 25and cannot effect actuation of the clamping members 28 either toward oraway from each other. The arcuate surface 29b has for its center ofcurvature the pivotal axis B of the movable contact structure;therefore, for the range of movement of the operating linkage defined byarcuate surface 29b, thearm 24 is maintained in predetermined angularrelation to contacts 2|, Fig. 6.

Throughout the entire movement of the operating linkage from onelimiting position to the other, the cam follower 3| is continuouslyoperatively related to the cam 29 to preclude actuation of the clampingmeans so long as and whenever the switch is open, and to preventmovement of the contacts into or out of engagement with each otherexcept at suitable contact pressures.

Preferably the cam 29 is provided with an integral stop or projection290 for limiting the movement of the contacts 2| away from fixedterminal 25; this stop may, of course, be dispensed with, particularlyif a suitable abutment is provided elsewhere in the path of one of themembers of the operating linkage.

Cam 29 may be integral with the terminal 22; preferably it is a separateelement suitably attached thereto as by the screws 81 which attach it toan extension 38, Fig. 7, projecting downwardly from the central portionof the terminal 22 between the extensions 22A for connection with busbars. The particular switch shown in Figs. 5 to 7 is an outdoordisconnect switch having a service rating of 6000 amperes at 15,000volts.

As shown in Fig. 7, several switches of the type shown in Figs. 5, 6,may be mechanically coupled for operation by a single operating member36 for use in multi-phase power circuits; each switch has its individualcam 29 for determining the limits within which its arm 24 is swung aboutits pivotal axis A to increase or decrease the contact pressure and fordetermining the limits within which the contacts 2|, 2| move with arm 24about pivotal axis B during maintenance of fixed angula'r relationbetween arm 24 and the movable contacts.

It is to be understood my invention is not limited to the particularconstructions illustrated and described as exemplary of my invention,but is coextensive in scope withthe appended claims.

What I claim is:

1. A switch comprising a contact, a pivotally mounted structureincluding a contact movable to engage said firstnamed contact, means forreleasably clamping said contacts to each other, an operating member forsaid movable contact and for said clamping means pivotally mounted uponsaid structure, and a cam having arcuate surfaces whose centers ofcurvature substantially correspond respectively with the pivotal axes ofsaid structure and of said member for sequentially precluding movementof said member about said axes to enforce actuation of said movablecontact and said clamping means in predetermined sequence.

2. A switch comprising a contact, a contact movable to engage saidfirst-named contact, means for releasably clamping said contacts to eachother, a member operable to actuate said movable contact and saidclamping means, and a cam having arcuate surfaces meeting at an abruptangle sharply to define a limit of a range of movement of said structurewithin which said operating member cannot actuate said clamping contactmembers and rotatable in opposite directions to clamp them to or unclampthem from said stationary contact structure, an operating membernon-rotatably attached to said threaded member between said contactmembers, and cam structure disposed in---a plane passing between saidcontact members substantially parallel to the paths of movement thereoffor controlling the position of said operating member relative to saidcontact members to preclude its rotation of said threaded member exceptwhen said contact members are in engagement with said stationary contactstructure.

4. A switch comprising a; cam, a fixed contact, switch blades pivotallymounted on opposite sides of said contact with said cam between them, asecondfixed contact having outside faces respectively engageable by theinner faces of said blades, clamping bars engaging the outer faces ofsaid blades to clamp them against said fixed contacts, a threaded memberpassing through said blades and axially rotatable to effect clampingmovement of said bars, and means for eflecting pivotal movement of saidblades and axial movement of said threaded member comprising a memberextending between said blades from said threaded member and continuouslyengaged by said cam between said blades.

5. A switch comprising a pair of fixed contacts, switch blades pivotallymounted on opposite sides of one of said contacts for movement effectingengagement of their inner faces with the outer faces of the other ofsaid contacts, a cam supported by one of said fixed contacts betweensaid blades, clamping bars engaging the outer faces of said blades, .athreaded member passing through said blades substantially midway oftheir length threadably to engage at least one of said bars to effectclamping of said blades upon said contacts, and an operating memberextending between said blades from said threaded member continuously toengage said cam sequentially to efiect pivotal movement of said bladesand axial rotation of said threaded member.

6. A switch, having a plane of general symmetry, comprising a pair ofstationary contact structures, a pair of contact members pivotallymounted upon one of said structures and movable between an open and aclosed circuit position, said members embracing said both stationarycontact structures when in said closed circuit position, a threadedmember movable with said contact members and axially rotatable inopposite directions relative thereto to clamp them or to unclamp themfrom said stationary contact structure, an operating membernon-rotatably attached to said threaded member and located between saidcontact members and in said plane of symmetry, one of said stationarycontact structures comprising cam structure between said contact membersand disposed in said plane of symmetry for controlling the position ofsaid operating member relative to said contact members and preventingaforesaid axial rotation of said threaded member except when saidcontact members are inengagement with said stationary contactstructures.

"I. A switch, having a plane of general symmetry, comprising a pair ofstationary contact structures, insulating means supporting saidstructures. a pair of contact members pivotally mounted upon one of saidstructures and movable between an open and a closed circuit position,

member and located between said contact members and in said plane ofsymmetry, and controlling means supported by one of said stationarycontact structures remote Irom said insulating 1 means and between saidcontact members and disposed in said plane of symmetry, said controlmeans comprising a cam for controlling the position of said operatingmember relative to said contact members, and tor preventing aforesaidaxial rotation of said threaded member except when said contact membersare in engagement with said stationary contact structures.

EDWARDS KNEASS.

